In general, a hand tool is used to tighten or loosen a workpiece. For example, a wrench comprises a main body. One end of the main body has a head. The head is provided with a drive shaft for connecting a drive member, such as a socket. The other end of the main body is provided with a handle for the user to hold thereon. When in use, one end of the drive member is connected with the workpiece and the other end of the drive member is connected with the drive shaft of the hand tool, such that the drive member can be rotated by pulling the hand tool to tighten or loosen the workpiece.
However, the hand tool is operated manually, so it is often encountered that the torque is insufficient to effectively lock the workpiece or that the workpiece is not easily removed. Besides, after the workpiece is loosened, the user needs to continuously rotate the hand tool to remove the workpiece, the operation is very inconvenient. Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve these problems.